Currently, it is required for scroll compressors being used in refrigerating devices and the like, a capability in which a single unit can efficiently operate under a wide range of conditions ranging from high-speed/high-pressure ratio conditions to low-speed/low-pressure ratio conditions.
In particular, in order to improve operating efficiency of a scroll compressor under low-speed/low-pressure ratio conditions, Japanese Laid-open Patent Publication 2011-149376 discloses a scroll compressor having a relief hole, which is shared by an A chamber and a B chamber of a compression chamber, formed on a bottom of a fixed scroll (on a fixed-side plate) and suppressing over-compression loss. It is noted that the A chamber refers to a compression chamber that is circumscribed and formed by an outer peripheral face of a lap of a movable scroll and an inner peripheral face of a lap of the fixed scroll. The B chamber refers to a compression chamber that is circumscribed and formed by an inner peripheral face of the lap of the movable scroll and an outer peripheral face of the lap of the fixed scroll. In Patent Literature 1 (Japanese Laid-open Patent Publication 2011-149376, relief holes are not individually provided to each of the A chamber and B chamber, and instead, by providing the shared relief hole, it is possible to suppress deterioration of efficiency due to an increase in dead volume while suppressing over-compression loss.